Experimental investigation of the performance and emissions of a heavy-duty diesel engine fueled with waste cooking oil biodiesel/ultra-low sulfur diesel blends

The major obstacle to biodiesel commercialization is the high cost of raw materials. Biodiesel from waste cooking oil is an economical source and thus an effective strategy for reducing the raw material cost. Using waste cooking oil also solves the problem of waste oil disposal. This study investigated the emissions of polycyclic aromatic hydrocarbons (PAHs), carcinogenic potencies and regulated matters, and brake specific fuel consumption from a heavy-duty diesel engine under the US-HDD transient cycle for five test fuels: ultra-low sulfur diesel (ULSD), WCOB5 (5 vol% biodiesel made from waste cooking oil + 95 vol% ULSD), WCOB10, WCOB20, and WCOB30. Experimental results indicate using ULSD/WCOB blends decreased PAHs by 7.53%-37.5%, particulate matter by 5.29%-8.32%, total hydrocarbons by 10.5%-36.0%, and carbon monoxide by 3.33%-13.1% as compared to using ULSD. The wide usage of WCOB blends as alternative fuels could protect the environment.     

Exhaust emissions and electric energy generation in a stationary engine using blends of diesel and soybean biodiesel

The present work describes an experimental investigation concerning the electric energy generation using blends of diesel and soybean biodiesel. The soybean biodiesel was produced by a transesterification process of the soybean oil using methanol in the presence of a catalyst (KOH). The properties (density, flash point, viscosity, pour point, cetane index, copper strip corrosion, conradson carbon residue and ash content) of the diesel and soybean biodiesel were determined. The exhaust emissions of gases (CO, CO₂,C_xH_y,O₂, NO, NO_x and SO₂) were also measured. The results show that for all the mixtures tested, the electric energy generation was assured without problems. It has also been observed that the emissions of CO, C_xH_y and SO₂ decrease in the case of diesel–soybean biodiesel blends. The temperatures of the exhaust gases and the emissions of NO and NO_x are similar to or less than those of diesel.     

A cycle simulation model for predicting the performance of a diesel engine fuelled by diesel and biodiesel blends

Among the alternative fuels, biodiesel and its blends are considered suitable and the most promising fuel for diesel engine. The properties of biodiesel are found similar to that of diesel. Many researchers have experimentally evaluated the performance characteristics of conventional diesel engines fuelled by biodiesel and its blends. However, experiments require enormous effort, money and time. Hence, a cycle simulation model incorporating a thermodynamic based single zone combustion model is developed to predict the performance of diesel engine. The effect of engine speed and compression ratio on brake power and brake thermal efficiency is analysed through the model. The fuel considered for the analysis are diesel, 20%, 40%, 60% blending of diesel and biodiesel derived from Karanja oil (Pongamia Glabra). The model predicts similar performance with diesel, 20% and 40% blending. However, with 60% blending, it reveals better performance in terms of brake power and brake thermal efficiency.     

Properties and use of jatropha curcas oil and diesel fuel blends in compression ignition engine

In the present investigation the high viscosity of the jatropha curcas oil which has been considered as a potential alternative fuel for the compression ignition (C.I.) engine was decreased by blending with diesel. The blends of varying proportions of jatropha curcas oil and diesel were prepared, analyzed and compared with diesel fuel. The effect of temperature on the viscosity of biodiesel and jatropha oil was also studied. The performance of the engine using blends and jatropha oil was evaluated in a single cylinder C.I. engine and compared with the performance obtained with diesel. Significant improvement in engine performance was observed compared to vegetable oil alone. The specific fuel consumption and the exhaust gas temperature were reduced due to decrease in viscosity of the vegetable oil. Acceptable thermal efficiencies of the engine were obtained with blends containing up to 50% volume of jatropha oil. From the properties and engine test results it has been established that 40–50% of jatropha oil can be substituted for diesel without any engine modification and preheating of the blends.     

Impact of waste cooking oil in biodiesel blends on particle size distributions from a city-car engine

Using biodiesel as a blending component in diesel engine has demonstrated to reduce hydrocarbon and particulate matter emissions. Literature showed that biodiesel type, engine architecture and test conditions deeply affect performance and emission characteristics. Among suitable biodiesel fuels, waste cooking oil (WCO) is considered very attractive due to the reduced environmental impact without sacrificing engine performance.This paper aims at investigating how mixing ratio of biodiesel from WCO and mineral diesel affects the particle size distributions of a current state of art small displacement diesel engine.Experimental tests have been performed on an up-to date light common rail diesel engine. Its complete operative field has been investigated. The results obtained show that the use of biodiesel blends from WCO reduces the total number of particles emitted from the engine with respect to the diesel fuel; the reduction is more evident as the percentage of biodiesel in the blend increases. The number of particles in WCO biodiesel soot with diameter smaller than 10 nm is reduced as compared to diesel fuel; the same trend is observed for diameters larger than 200 nm; comparable particle numbers were obtained in the ultrafine range (Dp < 100 nm).     

Performance of a diesel engine fueled by waste cooking oil biodiesel

A direct injection diesel engine fueled by a diesel/biodiesel blend from waste cooking oil up to B100 (a blend of 100% biodiesel content) indicated a combustion efficiency rise by 1.8% at full load. The soot peak volume fraction was reduced by 15.2%, while CO and HC concentrations respectively decreased by 20 and 28.5%. The physical and chemical delay periods respectively diminished by 1.2 and 15.8% for engine noise to pronounce 6.5% reduction. Injection retarding by 5° reduced NO_x to those original levels of B0 (a blend of zero biodiesel content) and combined respective reduction magnitudes of 10 and 7% in CO and HC at 75% load. Increasing the speed reduced CO and HC respectively by 26 and 42% at 2.36 times the droplet average strain rate. By coupling the turbulence model to the spray break-up and chemical kinetics models, increasing the injection pressure simultaneously reduced CO, HC and NO_x at 17% exhaust gas recirculation ratio.     

Exhaust emissions of diesel engines operating under transient conditions with biodiesel fuel blends

The transient operation of turbocharged diesel engines can prove quite demanding in terms of engine response, systems reliability and exhaust emissions. It is a daily encountered situation that drastically differentiates the engine operation from the respective steady-state conditions, requiring careful and detailed study and experimentation. On the other hand, depleting reserves and growing prices of crude oil, as well as gradually stricter emission regulations and greenhouse gas concerns have led to an ever-increasing effort to develop alternative fuel sources, with particular emphasis on biofuels that possess the added benefit of being renewable. In this regard, and particularly for the transport sector, biodiesel has emerged as a very promising solution.     

Autoignition reactivity of blends of diesel and biodiesel fuels with butanol isomers

The effect of n-butanol replacement by iso, sec or tert-butanol on the autoignition reactivity of diesel and biodiesel/butanol blends (the total alcohol content being 40% by vol.) was analysed. The study was performed in a constant volume combustion chamber under different initial temperatures (535 °C, ∼600 °C and 650 °C) and n-butanol substitutions. Results show that the effect of the alcohol in both pseudo-binary (diesel fuel/normal, sec, iso or tert-butanol) and pseudo-ternary (diesel fuel/n-butanol/iso, sec or tert-butanol) blends is not that expected from the autoignition properties of the pure isomers. When blended either with diesel or biodiesel fuels, tert-butanol increases the autoignition reactivity of the blend while the other two isomers reduce it. The partial substitution of n-butanol by tert-butanol could be an attractive method for increasing the alcohol content while keeping safe engine operation. Partial substitutions with iso or sec-butanol would promote partially premixed combustion conditions with limited pressure gradient peaks. Chemical kinetics simulations corroborate that the different consumption rates of active radicals from the butanol isomers are responsible for the observed trends. Biodiesel blends are less sensitive to the isomer replacing n-butanol due to its higher number of secondary CH bonds when compared to diesel fuel.     

Hydrogen dual-fuelling of compression ignition engines with emulsified biodiesel as pilot fuel

Dual-fuel compression ignition (CI) engine operation with hydrogen is a promising method of using hydrogen gas in CI engines via high-cetane pilot fuel ignition. However, hydrogen dual-fuel operation with neat pilot fuels typically produce: high NO_x emissions; and high combustion chamber pressure rise rates (leading to increased “Diesel knock” tendencies). While water-in-fuel emulsions have been used during normal CI engine operation to cool the charge and slow combustion rates in an effort to reduce NO_x emissions, these water-in-fuel emulsions have not been tested as pilot fuels during hydrogen dual-fuel combustion. In this work two water-in-biodiesel emulsions are tested as pilot fuels during hydrogen dual-fuel operation. Hydrogen dual-fuel operation generally produces at best comparable thermal efficiencies compared with normal CI engine operation, while the emulsified biodiesel pilot fuels generally increase thermal efficiencies when compared with the neat biodiesel pilot fuel during dual-fuel operation. There is also a clear reduction in NO_x emissions with emulsified pilot fuel use compared with the neat pilot fuel. The thermal efficiency increase is more apparent at higher engine speeds, while the NO_x reduction is more apparent at lower speeds. This is due to two conflicting effects (exclusive to emulsified pilot fuel) that occur in tandem. The first is the cooling effect of water vapourisation on the charge, while the second is the microexplosion phenomenon which enhances fuel-air mixing. The NO_x emission reduction is due to the emulsified pilot fuel lowering pressure rise rates compared with the neat pilot fuel, while the efficiency increase is due to a more homogeneous charge resulting from the violent microexplosion of the emulsified pilot fuel. Smoke, CO, HC and CO₂ emissions remain comparable to neat pilot fuel tests. Overall, emulsified pilot fuels can reduce NO_x emissions and increase thermal efficiencies, however not at the same instance and under different operating conditions. The general trends of reduced power output, reduced CO₂ and increased water vapour emission during hydrogen dual-fuel operation (with neat pilot fuels) are also maintained.     

柴油机燃用生物柴油的排放特性研究

生物柴油是由植物或动物脂肪通过酯化反应而得到。由于生物柴油无毒，可生物降解和再生，因此受到越来越多的关注。许多研究表明生物柴油的性质和普通柴油非常相似，因此它能直接被用到发动机上而不需要改动发动机的结构。作者对柴油机燃用以豆油和乙醇生产的生物柴油和普通O^x柴油时的排放污染物进行了对比和分析。结果表明：相对于普通O^x柴油，在纯生物柴油的污染物排放中，除NOx排放基本不变外，CO、HC和碳烟等有害物质的排放大大降低(分别降低了29．08％、24．98％和43．1％)。生物柴油与柴油掺混燃烧时，排放降低的效果与生物柴油在柴油中的混合比例成正比。     

柴油机燃用生物柴油的多环芳香烃排放试验研究

在一台直喷式增压柴油机上进行了生物柴油、柴油及其掺混油B20的排放特性试验,分别用玻璃纤维滤膜和“聚氨基甲酸乙酯泡沫（PUF）＋XAD．2”采集了尾气排放物中的颗粒相和气相多环芳香烃（PAHs）,并用色谱．质谱联用仪对PAHs进行了分析。结果表明：生物柴油的颗粒相、气相以及总PAHs的排放在大多数工况下低于柴油,其平均排放浓度均低于柴油。3种燃料的二环PAHs排放均在50％,生物柴油的三环以上PAHs所占比例均低于柴油。生物柴油PAHs排放的毒性当量与柴油相比有较大程度地下降。燃用生物柴油可以降低柴油机PAHs排放物对人体的危害。     

直喷式柴油机燃用生物柴油燃烧特性的研究

研究了柴油机燃用0#柴油和生物柴油的燃烧放热规律。通过对燃烧特征参数的计算分析,发现生物柴油的燃烧始点有所提前,滞燃期缩短;燃烧初期放热尖峰出现时刻对应的曲轴转角有所提前,瞬时放热率峰值下降;燃烧持续期延长。同时还比较了柴油机燃用生物柴油和0#柴油的经济性和排放特性,发现燃油消耗率上升12％左右,而各种排放污染物除NOx略有上升外,CO、HC和颗粒物(PM)均显著下降。     

发动机燃用生物柴油的性能研究

通过对比研究了柴油机燃用餐饮废弃油炼制的生物柴油、柴油及B50时在高原地区的动力性、经济性及排放特性。研究结果表明：在柴油机不进行任何调整的情况下,全负荷时,燃用生物柴油的发动机动力性降低6.8%,B50降低3%;燃用生物柴油有效燃油消耗率升高了13.8%;燃用B50在高速高负荷时柴油机热效率提高2.5%;无论在全负荷还是在部分负荷工况下,燃用生物柴油均能大幅度降低柴油机烟度、CO和HC排放,但会引起NOx排放量的上升。     

柴油机燃用生物柴油排气氧化催化实验研究

为改善高原地区车用柴油机的排放,进行了柴油机燃用生物柴油并加装柴油机氧化催化转化器（DOC）的发动机台架试验研究。结果表明,加装DOC后,柴油机烟度、CO和HC排放显著降低,对其动力性能、经济性能和NOx排放影响则很小。     

A novel approach to utilize esterified rice bran oil as an additive with gasoline and ethanol blends in MPFI SI engine.

ABSTRACT

In this work, we have attempted to add biodiesel as an additive with gasoline and ethanol blend to analyze the effect on performance and emission characteristics. The esterified rice bran oil is chosen as an additive. This focus of this work is to study the behavior of an SI engine for various blend proportions and to identify the optimum blend proportion that yields better results. MPFI engine was used to conduct the load test with gasoline as the base reference fuel. Blends of gasoline-ethanol and rice bran oil were prepared, and the tests were done for all the blends. The observed results were presented and discussed. Adding ethanol to the gasoline results in improved combustion that causes an increase in brake thermal efficiency and brake power. With esterified rice bran oil as an additive gives a reduction in specific fuel consumption, hydrocarbon emission, and carbon monoxide emissions. The optimum blends that have excellent benefits are identified.     

The use of Koroch seed oil methyl ester blends as fuel in a diesel engine

An experimental investigation was carried out on a small direct injection (DI) diesel engine, fuelling the engine with 10% (B10), 20% (B20), 30% (B30) and 40% (B40) blending of Koroch seed oil methyl ester (KSOME) with diesel. The performance and combustion characteristics of the engine at various loads are compared and analyzed. The results showed higher brake specific fuel consumption (BSFC) and lower brake thermal efficiency (BTE) for the KSOME blends. The engine indicated power (IP) was more for the blends up to B30, but found to be reduced for the blend B40 when compared to that of diesel. The engine combustion parameters such as pressure crank angle diagram, peak pressure, time of occurrence of peak pressure, net heat-release rate, cumulative heat release, ignition delay and combustion duration were computed. The KSOME blends exhibited similar combustion trend with diesel. However, the blends showed an early start of combustion with shorter ignition delay period. The study reveals the suitability of KSOME blends up to B30 as fuel for a diesel engine mainly used in generating sets and the agricultural applications in India without any significant drop in engine performance.     

Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO_x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.     

柴油乳化燃料的配制及应用

本文系统地介绍了柴油乳化燃料的配制设备、方法及其稳定性影响因素,其中阐明了除使用合适的乳化设备外,应用恰当的乳化方法,如混合膜生成法也可得到性能比较稳定的乳化燃料;利用配比合适的Ｓｐａｎ８０和Ｔｗｅｅｎ８０混合乳化剂可在油－水界面上形成络合物,使乳化液更趋稳定;乳化液两相密度差也是影响其稳定性的重要因素之一。文章最后对柴油乳化燃料的应用作了分类总结,指出柴油－甲醇(乙醇)－水复合乳化燃料和植物油燃料是代用燃料的今后发展趋势。     

非直喷式增压柴油机燃用生物柴油的性能与排放特性

研究了非直喷式增压柴油机燃用柴油一生物柴油混合燃料的性能和排放特性。未对原机作任何调整和改动,研究了不同生物柴油掺混比例的混合燃料对功率、油耗、烟度和NOx排放的影响。结果表明：非直喷式柴油机燃用生物柴油后柴油机功率略有下降,油耗有所上升,烟度大幅下降,NOx排放增加明显。油耗、烟度和NOx的变化均与生物柴油掺混比例呈线性关系,合适的生物柴油掺混比例即可以保持柴油机的性能,又可有效地降低碳烟排放,且不引起NOx排放的显著变化。对于该增压柴油机,掺混生物柴油对外特性下的排放影响最大,影响最小的为标定转速下的负荷特性。不论是全负荷还是部分负荷,燃用生物柴油时低速下的烟度降低和NOx上升幅度均比高速时大,而同转速下高负荷时烟度降低和NOx上升更为明显。     

Assessment of tree seed oil biodiesel: A comparative review based on biodiesel of a locally available tree seed

The present investigation is undertaken to investigate prospect of seeds of a locally available tree (koroch) for biodiesel production. The middle-size, evergreen koroch tree with spreading branches are available in Assam. The characteristics of koroch biodiesel and engine performance fueled by koroch biodiesel are also analyzed reviewing similar results available in the literature so as to ascertain its status. Twelve number of different tree seed oils, reported earlier, are considered for making the present comparative assessment. Though transesterification has been the common process for converting tree seed oil into biodiesel, as evidenced from the literature consulted in this study, but there have been variations of the chemical processes. Variations of the transesterification are attributed to (i) types of catalysis viz., acid (H₂SO₄) or base (KOH, NaOH, and NaOCH₃), (ii) reaction temperature, (iii) molar ratio, (iv) nature of reaction viz., single stage or multi-stage. The outputs of the reaction have also been found varying in terms of yield as well as quality. Quality of biodiesel, however, was found to influence by the nature of feedstock. The assessment of quality parameters was made either by ASTM D 6751 or EN 14214 standards. The major fuel properties such as calorific value, kinematic viscosity, cetane number and cloud point of the reference biodiesel (koroch biodiesel) are compared with the properties of five biodiesel obtained from non-edible tree seed (karanja, mahua, polonga, jatropha and rubber seed) and then ranked them in order of desirable property. No single biodiesel type could be found at top rank with reference to more than one property. With regards to viscosity, except rubber seed biodiesel, all other biodiesels (karanja, mahua, polonga, jatropha and koroch) fulfilled the ASTM D 6751 (1.9-6 cSt) as well as EN14214 (3.5-5) standards. Koroch biodiesel ranks 3rd, 3rd and 6th in case of kinematic viscosity, cetane number and calorific value amongst the biodiesel types considered for the present study. Cloud point of koroch, polanga, mahua, rubber, karanja and jatropha biodiesels are 4, 13.2, 5, 4, 12 and 4 °C. Further, properties of biodiesel were found to have influencing correlation with the fatty acid characteristics of the feedstock. Therefore, biodiesel with desirable properties could be expected form optimum mixing of different feedstock.Eleven number of different engine performance results pertaining to uses of biodiesel are also reviewed in this paper. Varying test conditions with reference to fuel types and blends, engine size and loading pattern are discussed. Engine performance results of koroch biodiesel were then compared with five similar tree-based biodiesel. It is observed that tree seed oil with more unsaturated fatty acids exhibits lower thermal efficiency compared to biodiesel having more saturated acids.